In the field called facility-based networks, a network using band-sharing transmission media has been conventionally used. These band-sharing transmission media generally have a very narrow band, but still continue to be used today in various types of facility equipment, because of advantages in cost, operation, and connectivity with existing devices.
To expand a facility-based network by connecting a plurality of devices, a bridging apparatus is generally used. By using the bridging apparatus, terminals that are connected to physically different networks can communicate with each other without paying attention to the presence of the bridging apparatus. Using the bridging apparatus also allows distribution of traffic.
A conventional bridging apparatus connected to a network checks for the presence of terminals on the network by using a response from each of the terminals to periodic broadcasting (Patent Literature 1). Another conventional bridging apparatus connected to a network checks for the presence of terminals on the network by polling each of the terminals (Patent Literature 2).